Disclosed herein is a method of forming a p-type zinc oxide thin film. A zinc oxide layer and an antimony oxide layer are alternately stacked one above another on a substrate, forming a superlattice layer. The superlattice layer is modified into a p-type zinc oxide thin film by annealing. Upon annealing, zinc atoms of the zinc oxide layer are diffused into the antimony oxide layer and antimony atoms of the antimony oxide layer are diffused into the zinc oxide layer.